Table 2.
Associations between garlic consumption and metabolic outcomes
| Outcome | Author | Year | Type of allium vegetables | Dose | Population | Type of studies in MA | No. Of trials and participants in MA | Duration | Metric of MA | Units | Effects model | Effect size (95% CI) | I 2%a | Publication bias |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Total cholesterol | Shabani, E., et al | 2018 | Garlic | Median: 1,000 mg/day (range 80–20,000) | Patients with dyslipidemia | Interventional studies | 31; NA | Median: 80.5 days (range 2–180) | WMD | mg/dl | REM | −16.87 (−21.01, −12.73) | 92.2 | Low riskb |
| Total cholesterolc | Ried, K., et al | 2013 | Garlic (powder, oil, garlic extract, or raw garlic) | Median: 900 mg/day (range 4–22,400) | Both healthy participants and patients with dyslipidemia | Interventional studies | 37; NA | Median: 12 weeks (range 2–52) | WMD | mg/dl | REM | −15.25 (−20.72, −9.78) | 77.0 | Noned |
| Total cholesterol | Ried, K., et al | 2013 | Garlic (powder, oil, garlic extract, or raw garlic) | Median: 900 mg/day (range 4–22,400) | Participants with short duration: 2–8 weeks | Interventional studies | 6; NA | Median: 12 weeks (range 2–52) | WMD | mg/dl | REM | −1.59 (−12.45, 9.27) | 0 | NR |
| Total cholesterol | Ried, K., et al | 2013 | Garlic (powder, oil, garlic extract, or raw garlic) | Median: 900 mg/day (range 4–22,400) | Participants with long duration: >8 weeks | Interventional studies | 31; NA | Median: 12 weeks (range 2–52) | WMD | mg/dl | REM | −17.20 (−23.10, −11.30) | 79.0 | NR |
| Total cholesterol | Ried, K., et al | 2013 | Garlic (powder, oil, garlic extract, or raw garlic) | Median: 900 mg/day (range 4–22,400) | Participants with TC baseline ≤200 mg/dl | Interventional studies | 8; NA | Median: 12 weeks (range 2–52) | WMD | mg/dl | REM | −5.73 (−14.31, 2.85) | 0 | NR |
| HDL | Shabani, E., et al | 2018 | Garlic | Median: 1,000 mg/day (range 80–20,000) | Patients with dyslipidemia | Interventional studies | 29; NA | Median: 80.5 days (range 2–180) | WMD | mg/dl | REM | 3.19 (1.85, 4.53) | 93.0 | Low riskb |
| LDL | Shabani, E., et al | 2018 | Garlic | Median: 1,000 mg/day (range 80–20,000) | Patients with dyslipidemia | Interventional studies | 28; NA | Median: 80.5 days (range 2–180) | WMD | mg/dl | REM | −9.65 (−15.07, −4.23) | 96.2 | Low riskb |
| Triglycerides | Shabani, E., et al | 2018 | Garlic | Median: 1,000 mg/day (range 80–20,000) | Patients with dyslipidemia | Interventional studies | 28; NA | Median: 80.5 days (range 2–180) | WMD | mg/dl | REM | −12.44 (−18.19, −6.69) | 93.6 | Low riskb |
| HDLc | Ried, K., et al | 2013 | Garlic (powder, oil, garlic extract, or raw garlic) | Median: 900 mg/day (range 4–22,400) | Both healthy participants and patients with dyslipidemia | Interventional studies | 30; NA | Median: 12 weeks (range 2–52) | WMD | mg/dl | REM | 1.49 (0.19, 2.79) | 33.0 | Noned |
| LDLc | Ried, K., et al | 2013 | Garlic (powder, oil, garlic extract, or raw garlic) | Median: 900 mg/day (range 4–22,400) | Both healthy participants and patients with dyslipidemia | Interventional studies | 26; NA | Median: 12 weeks (range 2–52) | WMD | mg/dl | REM | −6.41 (−11.77, −1.05) | 75.0 | Noned |
| Triglyceridesc | Ried, K., et al | 2013 | Garlic (powder, oil, garlic extract, or raw garlic) | Median: 900 mg/day (range 4–22,400) | Both healthy participants and patients with dyslipidemia | Interventional studies | 32; NA | Median: 12 weeks (range 2–52) | WMD | mg/dl | REM | −5.45 (−14.18, 3.27) | 71.0 | Noned |
| Fasting blood glucose ( FBG) | Shabani, E., et al | 2018 | Garlic | Median: 1,000 mg/day (range 80–20,000) | Diabetic patients | Interventional studies | 13; NA | Median: 80.5 days (range 2–180) | WMD | mg/dl | REM | −10.90 (−16.40, −5.40) | 94.9 | Noneb |
| FBG | Emami, S., et al | 2017 | Garlic (garlic food or supplement) | Median: 1,700 mg/day (range 500–40,000) | Healthy participants | Interventional studies | 3; NA | Median: 42 days (range 2–168) | WMD | mg/dl | REM | −0.68 (−6.16, 4.81) | 21.1 | Noned |
| HbA1c | Shabani, E., et al | 2018 | Garlic | Median: 1,000 mg/day (range 80–20,000) | Diabetic patients | Interventional studies | 7; NA | Median: 80.5 days (range 2–180) | WMD | mg/dl | REM | −0.60 (−0.98, −0.22) | 93.2 | Low riskb |
| HbA1c | Wang, J., et al | 2017 | Garlic supplement | Median: 900 mg/day (range 50–2,400) | Type 2 diabetic patients | Interventional studies | 2; 360 | 12 weeks | SMD | NR | REM | −6.93 (−10.71, −3.14) | 98.0 | Moderate riskb |
| HbA1c | Wang, J., et al | 2017 | Garlic supplement | Median: 900 mg/day (range 50–2,400) | Type 2 diabetic patients | Interventional studies | 2; 300 | 24 weeks | SMD | NR | REM | −13.25 (−15.83, −10.68) | 82.0 | Moderate riskb |
| Serum fructosamine | Wang, J., et al | 2017 | Garlic supplement | Median: 900 mg/day (range 50–2,400) | Type 2 diabetic patients | Interventional studies | 2; 120 | 1–2 weeks | SMD | NR | REM | −1.92 (−2.85, −0.99) | 75.0 | Noneb |
| Serum fructosamine | Wang, J., et al | 2017 | Garlic supplement | Median: 900 mg/day (range 50–2,400) | Type 2 diabetic patients | Interventional studies | 2; 172 | 3–4 weeks | SMD | NR | REM | −3.48 (−6.25, −0.71) | 96.0 | Noneb |
| Lipoprotein (a) | Sahebkar, A., et al | 2016 | Garlic supplement | Median: 900 mg/day (range 250–900) | Patients with dyslipidemia | Interventional studies | 6; 256 | Median: 12 weeks (range 8–52) | WMD | mg/dl | REM | 16.86 (−4.59, 38.31) | NR | 0.08e |
| Apolipoprotein B | Zeng, T., et al | 2012 | Garlic | Median: 890 mg/day (range 4–600,000) | Both healthy and hypercholesterolemic participants | Interventional studies | 4; 112 | Median: 12 weeks (range 2–48) | WMD | mg/ml | FEM | −0.03 (−0.13, 0.08) | 25.6 | 0.702e |
95% CI, 95% confidence intervals; FEM, fixed effects model; MA, meta‐analysis; NA, not available; NR, not reported; REM, random effects model; SMD, standard mean differences; WMD, weighted mean differences.
a
Heterogeneity was assessed with I 2 statistic.
b
Assessed by funnel chart.
c
Patients that requiring cholesterol‐lowering medical treatments were excluded.
d
Assessed by Begg's funnel plots.
e
Assessed by Egger's regression test.